1. Field of the Invention
The present invention is directed to an actuator for an ink jet print head of the layered type which includes an actuator unit and a fluid path unit that are coupled together.
2. Description of the Related Art
In the ink jet print head disclosed in Published Unexamined Japanese Patent Application No. Hei. 6-40035, a piezoelectric vibrating plate is bonded to a portion of an elastic plate which forms a pressure generating chamber, and flexure displacement of the vibrating plate changes the volume of the pressure generating chamber to cause the chamber to expel an ink droplet. The pressure displacement may occur over a relatively large area of the pressure generating chamber, and therefore the print head of this type is capable of stably jetting ink droplets.
High resolution (e.g., 720 dpi or higher) is required for both monochromatic and color printing by an ink jet printer. However, in a print head which utilizes piezoelectric vibrating elements to cause flexure displacement, the width of the vibrating elements limits a further reduction of the minimum pitch of the nozzle openings of each nozzle opening linear array.
One solution to this problem is to shift the nozzle openings of nozzle opening arrays by a preset number of dots vertically, i.e., in the direction in which the nozzle openings are arrayed.
As shown in FIG. 12, in the construction of this type of print head, actuator units A, B and C, each of which consists of a pressure generating chamber, a vibrating plate and a piezoelectric vibrating plate coupled together by sintering, are mounted on a single fluid-path unit D of a metal plate having a plurality of nozzle opening linear arrays.
One problem in the print head described above is that it is necessary to manufacture plural actuator units having ink discharging ports formed at positions corresponding to respective ones of the nozzle openings in the fluid path unit. Accordingly, increased labor and time are required for manufacturing and managing those component parts of the print head.